Insulation for transformer-coils.



No. 761,039. y Y PATENTBD MAY 24, 1904. 0. LE G. FORTESCUB. INSULATION POR TRANSFORMER GOILS APPLIOATION FILED SII-IPT= 30. 1903.

N0 MODEL.

BY gli] mi ohms Pneus co. PnoT0L|TH.... WASHINGTON, u. c

UNITED STATES Patented May 24, 1904.

PATENT OFFICE.

CHARLES LE G. FORTESCUE, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC 8c MANUFACTURINGv COMPANY, A CORPORATION OF PENNSYLVANIA.

INSULATION FOR TRANSFORMER-COILS.

SPECIFICATION forming part of Letters Patent No. 761,039, dated May 24, 1904.

Application filed September 30, 1903. Serial No. 175,224. (No model.)

T0 all whom it 11a/tty concern:

Beit known that I, CHARLES LE G. Fon- TEsoUE, a subject of the King of Great Britain, residing at Willrinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Insulation .for Transformer-Coils, of which the following is a specification.

My invention relates to coils for electrical apparatus, and particularly to the insulation of the coils intended for use in connection with high-potential circuits.

If the voltage applied to a coil is high, the difference of potential between adjacent layers of the coil may be such as to require very careful insulation; and the object of this invention is to provide a simple and effective form of insulation which may be readily applied.

My invention is illustrated in the accompanying drawings, in which- Figure 1 is a face view of a transformerfcoil constructed in accordance therewith. Fig. 2 is a sectional view on line II II of Fig'. 1. Fig. 3 is an end view of the coil shown in Fig. 1 with the outer layer removed; and Fig. I is a sectional view similar to Fig. 2, but showing a coil wound with layers in opposite directions.

The coil 1 here shown is of the form commonly employed in the construction of transformers of the shell type and comprises a plurality of turns of a suitably-insulated conductor 2, arranged in a plurality of layers.

A common method of decreasing the difference of potential between conductors of adjacentlayers is to wind the layers in the same direction-that is, when the last turn of a layer has been completed the conductor is crossed over from that side of the coil to the other side and the next succeeding layer is wound in the same direction across the coil as the previous one and in a similar manner. It is evident that the diderence of potential between the conductors of adjacent layers is thus reduced toene-half of what it would be if thecoil were wound in the ordinary manner.

in Fig. 1, or they may be distributed around the coil, thus avoidingv excessive bulging of any one portion thereof. The insulation of such coils has heretofore consisted of heavy strips of non-conducting material, such as treated paper, placed between adjacent layers and allowed to extend a suitable distance on both sides beyond the width of the layers. This form of coil is described in Patent No 652,027 granted to SE. Johanesson June .'19, 1900. This type of coil is ojectionable because of the large amount of space required by the insulating material and the diiiiculty experienced in winding and the care required in handling in order to preserve the coil in proper condition.

Another type of coil whichhas been employed in connection with high-potential apparatus is one in which a sleeve surrounds the first turn of each layer and is extended across the coil between the layers to the opposite face thereof. If the layers are wound in opposite directions, the alternate conductors on the face of the coil are exposed and are likely to be displaced and come into contact with each other. If the layers are wound in the same direction, all of the conductors on one face of the coil are exposed, and it is generallynecessary to extend the material between layers beyond the width o f the layers in order to obtain the proper insulation strength, leaving it-open to the same objection.

My invention provides for coils having the layers wound either in the same direction or in opposite directions a sleeve for the Iirstaud last turns of each layer, the sleeves being extended between the layers to the opposite `laces of the coil.

The special insulation employedV by me is clearly shown in Figs. 2 and 3 and comprises strips er sheets '7 of suitable insulatingmaterial-such, 'for example, as specially-prepared paper. The strips are of substantially double the width of the layers of winding to which they are applied, and each layer of the coil is provided with two strips', which are respectively l'olded around the outer turns ofthe layer to form sleeves and project in opposite directions over the opposite Afaces of the other turns of the layer to the edges of the coil. 1t `follows from this method of construction that adjacent layers of the coil are separated by 'four thicknesses of the insulation and that such insulation is readily applied and cornpactl y and securely disposed. The outer turns of each layer are 'ull y protected and lirmly secured in space and the complete coil has minimum dimensions.

The dimensions of the several strips may of course bc varied within considerable limits, and more than one strip may be folded around each outer turn, if desired.

Fig. 4 is a sectional View showing the insulation as applied to a coil having the layers wound in opposite directions, likenumerals referring to parts similar to those shown in Fig. 2.

Vhile I have illustrated and described my invention as embodied in transfornier-coils, it is not my desire or intention to limit it to such specilic Lmilication.V

I claim' as my invention l. A coil for electrical apparatus comprising a conductor wound in aplurality or' layers each having a plurality of turns, the iirst and last turns of each layer being provided with sleeves et' non-conductingI material which are extended across the coil between the layers.

2. A coil for electrical apparatus comprising a conductor wound in a plurality ot' layers each having a plurality or' turns, the several layers being completely separated by a plurality of strips of non-conducting material.

3. A coil for electrical apparatus comprising a plurality ot' layers wound in the same direction, the iii-stand last turns ol' each layer being' provided with sleeves which extend across the coil between the layers.

4. A coil for electrical apparatus comprising a conductor wound in apluralityol" layers each havinga plurality ot' turns, the lirst and last turns of each layer being provided with sleeves of non-conductingl material that preject in opposite directions across opposite Afaces ot' the layer.

5. A coil for electrical apparatus comprising an insulated conductor disposed in a plurality of superposed layers each consisting et' a plurality ot' side-by-side turns, and separating-strips of insulatingmaterial severally l'olded around the outer turns of each layer and projecting in opposite directions over the opposite faces of the layer.

In testimony whereo'tl I have hereunto subscribed my name this QSthday of September, 1903.

CHARLES LE (Sr. FORTESCUIC.

Vitnesses:

I. L. Gi-urrrrn, BIRNEY HINns. 

